JP3205968B2 - Antibacterial phosphate intercalation compound - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel antibacterial phosphate intercalation compound having an antibacterial action against various bacteria, and more particularly, it does not discolor over time and is kneaded with a resin or the like. Also when used as an antimicrobial resin composition,
The present invention relates to an antibacterial phosphate intercalation compound in which discoloration during kneading with a resin and discoloration over time of the antibacterial resin composition after kneading are small.

[0002]

2. Description of the Related Art Conventionally, in the case of inorganic antibacterial agents, a metal such as silver having an antibacterial action or a compound thereof is adsorbed to an adsorbent such as zeolite, activated carbon, activated alumina, silica gel and used for antibacterial purposes. It has been known. In addition, many organic substances have been proposed as organic antibacterial agents. However, the former inorganic type has a problem in that the metal having an antibacterial effect such as silver has insufficient stability and the antibacterial effect is persistent. Further, the latter organic system has disadvantages such as poor heat resistance, high vapor pressure, and relatively high toxicity.

One of the solutions to the problems of the conventional antibacterial agents is to provide an antibacterial composition comprising a heavy metal ion supported on a water-insoluble or hardly soluble phosphate or condensed phosphate. (Japanese Patent Laid-Open No. 2-965)
08). This antibacterial composition has a metal having an antibacterial action stably maintained in an active state, and has excellent durability of the antibacterial action and excellent heat resistance.

[0004]

However, when the above-described antibacterial composition is kneaded with a resin or the like and used as an antibacterial resin composition, the antibacterial resin discolors when kneaded with the resin or the antibacterial resin after kneading. There was a problem that the composition gradually discolored with time.

Accordingly, the present invention provides an antibacterial resin composition which does not discolor itself with time, and when used as an antibacterial resin composition after being kneaded with a resin or the like, the antibacterial resin composition after kneading may be used. An object of the present invention is to provide an antibacterial interphosphate compound which does not gradually discolor over time.

[0006]

That is, the antibacterial phosphate intercalation compound of the present invention comprises a layered phosphate obtained by intercalating a metal ion having an antibacterial action and an alkali metal ion by an ion exchange method. It is a feature. This antibacterial phosphate intercalation compound does not lose many advantages such as persistence of the antibacterial effect, stability of the antibacterial substance and heat resistance. Also, when used as an antibacterial resin composition, discoloration during kneading with the resin and further, discoloration of the antibacterial resin composition after kneading with time are small.

The above-mentioned antibacterial phosphate intercalation compound of the present invention is prepared by bringing a layered phosphate into contact with an aqueous solution of an alkali metal and a metal having an antibacterial action, and performing ion exchange.
Can be easily manufactured.

As the metal ions having an antibacterial effect used in the present invention, silver ions, copper ions, zinc ions and the like can be preferably used, and not only one kind of these metal ions but also several kinds thereof are intercalated into a layered phosphate. May be. As the alkali metal ion, lithium ion, sodium ion and the like can be preferably used, and not only one kind but also several kinds may be intercalated into the layered phosphate.

As a layered phosphate serving as a support for a metal ion and an alkali metal ion having an antibacterial action, a phosphate of a tetravalent metal such as zirconium phosphate and titanium phosphate, and aluminum tripolyphosphate can be preferably used. . Phosphates of tetravalent metals are available from A. Clearfield, G. Albe
rti and U. Costantino “Inorganic Ion Exchange Mat
erials ", A. Clearfield ed, CRC Press, Inc., USA, although compendium is described in Chapter 3 (1982), M ⁴ (HP
O ₄ ) ₂ . It is represented as nH ₂ O (M ⁴ ; tetravalent metal), and α-form monohydrate, γ-form dihydrate and the like are generally well known. These are solid acids which are hardly soluble in water and have cation exchange ability. Ion exchange capacity is based on hydrogen phosphate (HPO ₄
^The theoretical ion exchange capacity is 6.64 meq / g for α-type zirconium phosphate (hereinafter abbreviated as α-ZrP) and α-type titanium phosphate (hereinafter α-Ti)
7.76 meq / g, γ-type zirconium phosphate (hereinafter abbreviated as γ-ZrP), 6.27 meq / g,
γ-type titanium phosphate (hereinafter abbreviated as γ-TiP) is 7.25.
meq / g. Aluminum tripolyphosphate is represented by AlH ₂ P ₃ O ₁₀ .2H ₂ O (hereinafter abbreviated as AlP), and has a theoretical ion exchange capacity of 6.29 meq / g.
It is.

The reaction of intercalating a metal ion and an alkali metal ion having an antibacterial effect on the layered phosphate is considered to be an ion exchange reaction with a proton of a hydrogen phosphate group. In the production of the antibacterial phosphate intercalation compound of the present invention, a part or all of the ion-exchangeable protons of the layered phosphate is ion-exchanged into a metal ion and an alkali metal ion having an antibacterial action. And it can be carried out at ordinary temperature to high temperature by a general batch method or column method. As described above, after the metal ion and the alkali metal ion having an antibacterial action are intercalated into the layered phosphate by ion exchange, the solid phase is filtered and washed to remove unreacted ions, and then dried. As a result, a layered phosphate in which a metal ion and an alkali metal ion having an antibacterial action are intercalated, that is, an antibacterial phosphate intercalation compound is obtained.

[0011]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples. However, the present examples are described for illustrative purposes only.
The present invention is not limited by these examples.

Example 1 (Production method of antibacterial phosphate intercalation compound of the present invention) A nitrate (AgNO ₃ , Cu (NO) of a metal having an antibacterial action having a composition shown in Table 1 was added to 20 g of layered phosphate. ₃ )
₂ , 400 ml of Zn (NO ₃ ) ₂ ) aqueous solution is added, and then a predetermined amount (described in Table 1) of an aqueous solution of an alkali metal hydroxide (LiOH, NaOH) is gradually added with stirring, and the mixture is stirred for about 4 hours. Continued contact. Thus, the layered phosphate was intercalated with a metal ion having an antibacterial action and an alkali metal ion. Next, the solid phase is separated by filtration and washed with water for 1 hour.
It was dried at 00 to 110 ° C for about 5 hours to obtain the antibacterial phosphate intercalation compound of the present invention.

Comparative Example 1 (Method for Producing Conventional Antimicrobial Composition Containing No Alkali Metal Ion) Using 400 ml of an aqueous solution of a metal salt of an antibacterial metal having the composition shown in Table 1, an alkali metal hydroxide was prepared. In the same manner as in Example 1 except that the aqueous solution of
A conventional antimicrobial composition containing no alkali metal ions was prepared.

Table 2 shows the contents of the metal ions and the alkali metal ions having an antibacterial action of the samples prepared in Example 1 and Comparative Example 1 described above.

Example 2 (Antibacterial test) The minimum inhibitory concentration (hereinafter abbreviated as MIC) of various kinds of bacteria of the antibacterial compositions obtained in Example 1 and Comparative Example 1 was measured by an agar dilution method. The measurement was performed as follows:

In a sterilized petri dish, 10 ml of an ordinary agar medium having a different concentration of the antibacterial composition is prepared. A fixed amount of the test bacterial solution is placed on each of these media, dried, and cultured at 30 ° C. Then, when there is no change (proliferation or decrease) in the state of the bacterium, the minimum concentration (MIC) of the antimicrobial composition-containing concentration is determined from the medium in which growth is completely inhibited. Staphylococcus aureus (Staphylococcus aureus), Escherichiacoli (Escherichia coli), Bacillus subtil
is (Bacillus subtilis) and Pseudomonas aeruginosa (Pseudomonas aeruginosa) were used.

Table 3 shows the results. It can be said that the smaller the MIC value, the stronger the antibacterial activity, but it can be seen that the antibacterial activity is equivalent to that of the conventional product.

Example 3 (Discoloration test) The discoloration test was carried out by the following method: (Resin kneading discoloration test) To 100 parts of low density polyethylene powder, each of the samples obtained in Example 1 and Comparative Example 1 was used. 5
And 5 parts of titanium oxide were added, mixed well, and heated and melted in a crucible at 190 ° C. for 20 minutes. After cooling, and after 50 hours of light irradiation using a fadeometer, the change in color was compared. The color was compared with the Munsell color chart and indicated by the Munsell value. Table 4 shows the results.

(Discoloration test of antibacterial phosphate intercalation compound itself) Changes in color immediately after preparation and after irradiation with light with a fadeometer for 50 hours were compared. The color was represented by a Munsell value as in the resin kneading test. Table 5 shows the results.

[0020]

The antibacterial phosphate intercalation compound of the present invention comprises:
It has the same antibacterial activity as a conventional antibacterial composition containing no alkali metal ion, and has an antibacterial resin composition after discoloration and kneading with a resin or the like which is discolored over time as compared with conventional products. The discoloration of the product over time is much less (see Tables 4 and 5).

In producing the antibacterial phosphate intercalation compound of the present invention, the antibacterial phosphate intercalation compound has an alkali metal ion and an antibacterial effect as compared with a method of intercalating only a metal ion having an antibacterial effect into a layered phosphate. By simultaneously performing ion exchange with metal ions, the yield of metal ions having an antibacterial effect is improved (see Tables 1 and 2).

[0022]

[0023]

[0024]

[0025]

[0026]

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI C01D 1/00 C01D 1/00 C08K 3/32 C08K 3/32 9/02 9/02 (56) References JP-A-5-95 32406 (JP, A) JP-A-2-96508 (JP, A) JP-A-63-88109 (JP, A) JP-A-1-282109 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C01B 25/37 CA (STN)

Claims (2)

(57) [Claims] 1. An antibacterial phosphate intercalation compound comprising a layered phosphate in which an alkali metal ion and a metal ion having an antibacterial action are intercalated. 2. The metal ion having an antibacterial action is selected from silver ion, copper ion and zinc ion.
4. The antibacterial phosphate intercalation compound according to item 1.